Red marks in a number grid puzzle appear on the wrong cell or not at all

Players want a number the moment it clashes with another, but checking against the stored answer spoils alternative paths and marking only one of the two clashing cells confuses them. This entry shows what to compare, which cells to mark and when the grid counts as finished.

Why this works

The rules say what is wrong, the solution only says what is expected. Judging by the rule marks exactly the cells that clash now, and never rejects a different grid that is perfectly valid.

When not to use it

Marking clashes live gives away mistakes, which spoils puzzles where finding the error is the challenge, or a hard mode. There, show nothing until the player asks, and then check the whole grid at once.

In the full entry

• What to build, step by step
• Starting values and the reason for each
• 4 common mistakes and the fix
• A diagram of every state
• 35 lines of example code with 4 checks that pass
• How your AI shows you that it works

Say this to your AI

Use the Spielerando entry "Red marks in a number grid puzzle appear on the wrong cell or not at all" (read_entry number-grid-conflict-highlight) in my game. Build it step by step, and show me how you checked that it works.

Or skip this and connect the MCP: your AI then finds all of this by itself.Connect the MCP